I know this would be a huge thing to do, however this is why I will continue to use outlook directly connecting to hotmail rather than roundcube for the moment.
When I use outlook, (using the hotmail connector) it syncs all my folders and emails accordingly. So any folders I create in hotmail sync to outlook and any folders I create in outlook also sync back to hotmail. Also the emails that I put into these folders sync between hotmail and outlook accordingly also.
I have a few email addresses (as well as family members who also have email addresses) and I require my folders to sync so that no matter where I access it from (outlook, hotmail online, my smartphone, or roundcube if I were to use it) the folder structure and location of my organised emails would always be the same.
I would be able to create separate accounts within my mail server to add these accounts to it, so having multi-accounts layout is not essential, however it could be an additional feature on top of this.
I have added a photo of my current outlook setup, (with some of the more personal stuff changed to generic names), this layout is how I would envisage it appearing in roundcube, I have added an example of the roundcube layout to illustrate how it could look there.
This would allow me to keep my folders automatically organised and synced with hotmail, as outlook does already, rather than having to do it manually on 3 different computers, my phone and my hotmail accounts, whilst having a central point to link it to, so I don't have to have outlook downloading them from hotmail on every computer.
I hope this makes sense (hence the visual aid to assist with my description).
